The New York State Department of Health 1.2 MV high-voltage electron microscope facility is available to qualified members of the scientific community. Funds are requested to develop electron energy-loss spectroscopy (EELS) of wet biological specimens at high acceleration voltage (1.2 MV). In EELS, the intense microprobe beam enters the entrance apertures of a differentially-pumped environmental chamber (DIFPEC), passes through the wet specimen, out of the exit apertures of the chamber, and down the column to the energy-loss spectrometer beneath the column. The characteristic energy losses permit identification of the elements present and enable their concentrations to be estimated. For the important intracellular light elements, EELS is several orders of magnitude more sensitive than XMA. By keeping the specimen wet, we hope to improve estimates of intracellular ion distributions since freezing and other techniques frequently gave anomalous distributions in past work. It is believed that the EELS is more sensitive at high accelerating voltages. This claim will be explored and quantitated. The developed analytical capability will be used to collaborate with cell physiologists in carrying out investigations in the mechanisms of transport and accumulation of ions in cells.